1. Field of the Invention
The present invention relates to a reusable system for the construction of roadways and equipment support surfaces in areas having poor ground integrity characteristics. More particularly, the present invention relates to a system of durable mats which can be interconnected to form roadways and/or equipment support surfaces. More particularly still, the present invention relates to a reusable system of mats which can be quickly and easily positioned in a single layer to form roadways and/or equipment support surfaces, and which can thereafter be easily removed and stored until needed again.
2. Description of the Related Art
Individual wooden boards have long been utilized to construct temporary roadways and equipment placement surfaces in remote and/or undeveloped areas where the terrain lacks sufficient integrity to properly support trucks or other heavy equipment. However, the use of individual wooden boards or planks for this purpose suffers from some very significant disadvantages. First, because such a large number of wooden boards are generally required to construct a roadway and/or equipment support surface, the use of wooden boards is typically very labor intensive, since each board must be individually positioned and then nailed or otherwise secured in place. Likewise, removal of said roadways and/or equipment support surfaces can also be a very time consuming and labor intensive process, since the boards must be separated or pulled apart prior to being removed from the location.
Second, the use of individual wooden boards to construct temporary roadways and equipment support surfaces in remote and/or undeveloped areas can also be very expensive, both in terms of the aforementioned labor requirements, as well as the raw materials which are needed to construct said roadways and support surfaces. A significant investment is often required to purchase enough wooden boards to construct the roadway and/or surface in question. Thereafter, once the boards have been installed, exposure of the boards to the elements, particularly in hot, humid environments such as marshes or wetlands where said board roads and surfaces are routinely utilized, invariably leads to degradation and deterioration of the wooden boards. For this reason, boards are often discarded after being used only once and, in particularly harsh environments, may even need to be replaced on location during the course of a particular job. Because new wooden boards are continuously needed to replace older boards that have decayed or deteriorated, the cost of said board roads and support surfaces seldom remains constant. Moreover, the continuous need for additional wooden boards also contributes to the depletion of a natural resource, i.e. timber stock, which in turn acts to drive up the cost of the new wooden boards which must be purchased.
Third, there are a great deal of functional problems associated with the use of individual wooden boards for the construction of temporary roadways and equipment support surfaces. For instance, because there are a number of seams between the individual boards, and also because the boards are subjected to different types of loading, the boards often tend to work themselves loose from each other. This can create large gaps in the roadway which in turn exposes the underlying terrain to the elements. Additionally, the nails which are used to secure the individual boards to each other often become exposed, thereby presenting a hazard to both the motorized and foot traffic using the roadway and/or support surface.
Fourth, use of individual wooden boards to construct roadways and/or equipment support surfaces also creates significant environmental concerns. Because wood is a highly absorbent material, wooden boards have a tendency to soak up the various contaminants which inevitably come in contact with said boards during the drilling process. These contaminants include a wide variety of substances, such as mud, drilling fluids, diesel, and oil and grease leaked from vehicles using the roadways and/or equipment support surfaces. When rain falls on these boards, these contaminants have a tendency to leech out of said boards and into the surrounding environment.
More recently, in an effort to overcome the problems associated with the use of separate wooden boards, a variety of mat systems have been developed. These systems generally utilize multi-layered wooden mats which can be laid down to form roadways or other support surfaces. These mats, which are typically constructed of individual boards or planks joined together in various configurations, interconnect or intermesh in order to form a continuous or nearly continuous roadway and/or support surface.
While these mat systems may arguably represent an improvement over the use of individual boards, the aforementioned conventional wooden mat systems still suffer from a number of very serious shortcomings. Although conventional mats may reduce labor requirements compared to individual wooden boards, significant amounts of time, effort and manpower are still needed to install said mats on location since most if not all of these conventional mat systems require the use of multiple layers. Thus, an initial layer must first be installed, then at least one additional layer of mats must be installed on top of said first layer. This multi-layer requirement leads to significant redundancy of effort in connection with both the installation and removal of said mats.
Additionally, the design of conventional mat systems can lead to degradation of the ground underlying said mats, as well as the structural integrity of the mats themselves. Because the individual mats of conventional mat systems are constructed of various configurations of wooden boards or planks, the mats all contain gaps or seams between said boards and/or planks. As rain falls on said mats, the rain water passes through the seams of said mats and mixes with the underlying soil to make mud. Trucks and other heavy equipment passing over the mats place a load on said mats which in turn can cause this mud to be pumped up through the numerous gaps or seams of the mats. This pumping action creates voids beneath the mats which, over time, can lead to severe deformities in the roadway surface. Because the mats bridge over these underlying voids, the mats thereafter have a tendency to break or splinter when subjected to normal loading.
Conventional wooden mats also suffer from significant rotting problems, because the mats can become inundated with rain water and various other contaminants from above, as well as mud from below. This mixture of water, mud and other contaminants can invade into the seams or gaps between the boards of said mats, causing the wooden mats to rot from within. As a result, just as with individual boards, conventional mats must be frequently repaired and, in some cases, entirely replaced. Although conventional mat systems are designed to be reusable, the mats are still subject to significant repair and replacement expense.
The design of these conventional mats often leads to significant environmental problems, because mud and other contaminants can saturate the mats and collect within the numerous seams or gaps of said mats. While this may not necessarily present a problem during the course of a particular job, these contaminants can be spread to other (often pristine) areas when the mats are utilized on subsequent jobs. Further, although many regulatory bodies require the use of retaining levees around drill sites, there is generally no such requirement for roadways. Thus, a conventional mat which is used at the drill site on one job (and which is exposed to all of the contaminants present at said drill site) may be used on a roadway for the next job. Because these roadway mats often contain contaminated mud from a previous job, these contaminants will be permitted to leech into the surrounding environment and, because there are generally no retaining levees around said roadways, this contamination may not even be subject to containment. While it may be desirable to wash these conventional mats after each job to prevent such environmental contamination, there is currently no cost-effective way of thoroughly cleaning these conventional mats.
Examples of existing mat systems are as follows:
Robishaw, U.S. Pat. No. 2,639,650, discloses a series of metal mats, which provide a corrugated surface. This patent provides a discontinuous bearing surface for contact with the terrain, and does not provide a substantially smooth working surface. Furthermore, assembly of this mat system requires intricate fitting by side-to-side sliding action and fitting of numerous corresponding corrugated shapes. The Robishaw patent does not provide connecting means for lateral mat placement.
Smith, U.S. Pat. No. 2,652,753, discloses a series of wooden mats of multiple layers constructed of wooden boards, intermittently-spaced longitudinally to provide an intermeshing end to end connection.
Leyendecker, U.S. Pat. No. 2,819,026 discloses a mat system comprising a plurality of wooden sections interfitted in a longitudinal manner and retained by lateral strapping means. Assembly of this system requires "weaving" of a strapping means between adjacent connected sections. Further, the disclosures make no provision for lateral section attachment or connection.
Hart, U.S. Pat. No. 2,912,909, discloses a mat system comprising a plurality of wooden sections interfitted in longitudinal and lateral manners to create substantially flush upper and lower surfaces. To effect a substantially continuous contact layer support, alternating sections must be precisely placed at measured distances from each other to facilitate later placement of the interconnecting system.
Davis, et al, U.S. Pat. No. 4,289,420, discloses a wooden mat for use as a temporary roadway comprising longitudinally and laterally spaced interdigitated boards. This system requires intricately precise relative placement of each mat section involving substantial installation time. Further, this disclosure makes provision for lateral expansion in only a single lateral direction.
Penland, Sr., U.S. Pat. No. 4,462,712 discloses a method and apparatus for construction of a flooring system comprising a plurality of wooden boards with longitudinally locking tabs and slots. This patent makes no disclosure of means to facilitate lateral connection or expansion of said flooring mats.
Waller, Jr., U.S. Pat. No. 4,600,336, discloses an interlocking wooden mat system comprising wooden mats with intermeshing longitudinal and lateral boards retained by tie-in planks nailed to the main mat sections. Disclosures of this patent reveal interconnecting means requiring intricate and complex assembly procedures involving substantial installation time.
Hicks, U.S. Pat. No. 4,875,800 discloses a system identically similar individual mats, each comprised of a layer of parallel boards attached to a half layer of parallel boards disposed perpendicular to the first layer. When two layers of these mats are laid together a 3-layer surface is formed.
Similarly, U.S. Pat. No. 4,973,193 to Watson, et al, U.S. Pat. No. 5,020,937 to Pouyer; U.S. Pat. No. 5,032,037 to Phillips, et al; and U.S. Pat. No. 5,273,373 to Pouyer all disclose mat systems comprising individual mats constructed of various configurations of boards or cross-members. Each of these patents disclose mat systems which must be installed in multiple layers. Moreover, each of these patents disclose mats which are permeable and, thus, susceptible of being invaded by water, mud and other contaminants.
Springston, et al, U.S. Pat. No. discloses a system of portable mats for the construction of runways and other support surfaces. The mats disclosed in this patent must be joined together using bolts or other means.